Just a bit of background........

     I'm not a potential builder of a Harryproa, as they don't meet my
criteria, but rather interested in building a 30' catamaran or
thereabouts.   One of my biggest priorities is achieving the most
payload for the size cat I'm looking at. The two catamarans under
consideration are wood epoxy, one entirely plywood, the other with a
strip planked lower hull section.

    Rob immediately suggested building from foam sandwich, and offered
a lot of information on substitution of infused foam sandwich for
plywood, including weight savings that look too good to be true, but
seem to be borne out the further I research the subject.   Having found
a "local" source for construction foam (Divinicell), at a price I can
swallow, though much higher than the numbers Rob quotes in Australia,
I'm in the process of examining the feasibility of building this way,
and how I can pare costs down a bit without compromising the structure.

    I joined this group at Rob's suggestion, hoping to gain a better
understanding of the details of his intelligent infusion process, which
are at best murky.... at least to me.   Watching Utube videos of
infusions, some seem to involve an almost absurd number of layers of
various disposable, materials, others only a few.  Some folks do it on
male molds, others on female molds, some infuse one side of a part only,
and others seem to manage to infuse an entire sandwich in one go.  Foam
with cuts in opposite direction on opposite sides, foam with
perforations and knife slices, plain foam, distribution mat, peel ply,
and on and on. Porting the resin in, and porting the vacuum, are both
obviously important, and the distribution of those ports would seem to
be critical to getting the infusion right.    An entire half of a 30'
catamaran hull would be a big failure if things didn't work out. Enough
of a failure that wetting it out manually and vacuum bagging followed by
the inevitable hand finishing would not seem so bad by comparison.    I
personally find the idea of losing even a single piece of that size a
bit more than I can stomach, and losing one, there is no guarantee that
the next will work   ;-)

      With that in mind, I've been going through the photos, and am
just beginning to work my way through old posts to glean what
information I can.   I'm a year or more off from beginning my own
project, and plan to do some test pieces and more research and reading
during that time.

                                                   H.W.

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